It has often been observed on laced shoes, whether they have a high or low tongue, that the knot and/or loop of the lace frequently comes undone, for example when playing sport, when handling children after having tied the lace, when the lace accidentally hooks onto something; or when the lace has a relatively inflexible texture (for example made from leather or nylon).
Such unwanted undoing is not only a nuisance, because of the knots and loops that it is constantly necessary to re-do, but may in particular be a source of incidents and accidents, more particularly with children, who risk walking on their laces and falling.
The same applies with sportspersons, who may fall because of an undone lace during a match or race, with cyclists and with motorcyclists, where this coming undone may even put their life in danger.
Amongst workers on sites who are working with machines and/or at a height the coming undone may give rise to serious accidents (or even death).
Many devices for preventing laces coming undone have been developed during the past few years, for example the device for preventing undoing disclosed in the patent U.S. Pat. No. 4,780,936, but the majority of them cover the knot and not the loops of the knot. Consequently they do not resolve the problem of the loops of the knot catching. In addition they fall off as soon as the lace is untied, for example when taking the shoe off.
The U.S. Pat. No. 5,042,119 discloses a device for securing, covering and containing the ends of the laces. It consists of a band of cloth in three parts, the central part of which is fixed, in particular stitched over the whole length of the shoe, to the part corresponding to the instep. In order to completely cover the knotted lace, the invention described in the U.S. patent comprises two foldable parts which are superimposed over the entire length of the instep and which are attached to each other, for example by a zip or other similar means. This therefore procures a kind of case which completely surrounds the knot and the lace loops and which covers the entire top of the shoe.
The drawback of such a device is that it is not simple to manufacture nor to position, the stitching of the central part having to be carried out on a shoe already partly stitched, the device leaving no freedom of movement since it imposes a certain degree of rigidity, and in particular such a device cannot be adapted to all shoes, for various reasons. First of all, this type of bulky device cannot be conceived on a town shoe nor even on a mixed shoe. It can only be conceived for sports shoes related to disciplines in which the foot remains relatively fixed, for example for cycling shoes. In addition, for one and the same shoe, the device is not very flexible with regard to the width and causes additional discomfort for an athlete with large feet. This is because the passage holes for the laces fit on the top of the foot and the separation between the holes is not variable but is limited by the width of the central part.